Solar-Wind Kinetic Power Intercepted by Mercury's Magnetosphere and the Coupled Fraction

The solar wind at Mercury is denser and more energetic per unit area than at any other planet, while the magnetosphere it strikes is the smallest in the Solar System. This paper computes the kinetic energy flux of the wind from published mean density and speed, the total power intercepted by the magnetospheric cross-section at the observed standoff distance, and the power coupled into the magnetosphere under one-percent and ten-percent coupling efficiencies. The headline results are: dynamic_pressure_nPa = 9.37; kinetic_energy_flux_W_m2 = 0.002; magnetosphere_cross_section_m2 = 3.665e+13. The intercepted power is of order ten to the eleventh watts, of which even a one-percent coupling supplies ten to the ninth watts to magnetospheric processes, a supply that must be set against Mercury's rapid, minutes-long cycle of loading and unloading magnetic energy.